Electric immersion heater



y 31, 1949- E A. P. CHARBONNEAU ELECTRIC IMMERSION HEATER Filed May 15',1948 2 Shets-Sheet 1 3 1949. A. P. CHARBONNEAU ELECTRIC IMMERSIQN HEATER2 Sheets-Sheet 2 Filed May 13, 1348 Patented May 31, 1949 UNITEDELECTRIC IMMERSION HEATER Allan P. Charbonneau, Wauwatosa, Wis, assignorto Cutler-Hammer, Inc., Milwaukee, Wis., a

corporation of Delaware Application May 13, 1948, Serial No. 26,731

(Cl. 2l938) 7 Claims.

This invention relates to electric heaters equipped with mounting means.

The invention which is particularly applicable to immersion type waterheaters carries forward the teachings of the Hadaway Patent No. 1,281,-157, October 18, 1918, said patent teaching end securement and sealingof a sheathed heater to a copper plate which equipped with gasket closesthe entrance opening for the heater into a fluid container, the gasketand plate being clamped to the container by a centrally open mountingplate, and protecting the latter from attack by the fluid withim thecontainer.

The present invention has among its objects to improve said Hadawayconstruction in numerous respects including greater ruggedness for agiven amount of material employed and better support and protection forthe electric terminals of the heater.

Another object is to utilize an insulating terminal block for the heateras a means for holding the mounting plate in assembled relation with theheater when the heater terminals are fixed to terminal plates carried bysaid block.

Another object is to provide for securement of the heater and itsmounting parts in assembled relation without even extending the heatersheath through or into engagement with the mounting plate.

Another object is to provide a gasket plate formed to receive and per seretain in place thereon the gasket to be clamped against the receptacle.

Another object is to provide a mounting which without change except inthe number of openings provided in the gasket plate may be employed forone or more heating elements, as for example a single tubular heaterbent into a hairpin form or elongated coil form, or alternatively aplurality of elements each of hairpin or other form.

Other objects and advantages will hereinafter appear.

The accompanying drawing illustrates a preferred embodiment of theinvention which will now be described, it being understood that theembodiment illustrated is susceptible of various modifications withoutdeparting from the scope of the appended claims.

In the accompanying drawing,

Figure 1 is a side elevational view of a heater inclusive of mountingmeans, the heater being shown as projecting through a tank wall, thetank wall and certain parts of the heater mounting means being shown insection;

Fig. 2 is a rear elevational view of the heater mounting means shown inFig. 1;

Fig. 3 is a front elevational view of the heater mounting means shown inFig. l, certain of the terminal plates being omitted;

Fig. 4 is an edge view of the mounting plate;

Fig. 5 is a section through the gasket plate taken on line 55, Fig. 2;

Fig. 6 is a sectional View through the terminal block shown in Fig. 3,the section being taken on line G-6, Fig. 3, and certain associatedelements being shown in assembled relation therewith, and

Fig. '7 is a rear elevational view of the terminal block shown in Fig.3.

The heater shown in Fig. l is a so-called tubular heater l9 bent intohairpin form. This heater preferably comprises a helical resistor I2surrounded by a seamless and bendable tubular metal sheath [3 from whichit is spaced and insulated by a highly compacted mass of granularinsulating material it, said helix having straight terminal leads 55(Fig. 6) extending from the ends of the sheath. The terminal leads havetheir inner ends embedded in the compacted granular insulation and mayor may not be sealed within the sheath. This type of element which iswell known may be formed in any of the various ways now known, whereasas will appear the mounting means to be described is applicable to othertypes of heating elements.

Briefly set forth the heating element it has the terminal portions ofits sheath projected into and snugly fitting within openings in a gasketplate I! carrying a gasket 18, said gasket plate to be clamped againstthe receptacle wall l9 by a mounting plate 2% which commonly is boltedto the wall 19, one bolt 2| being shown in Fig. 1. The mounting plate 20is centrally recessed to receive a shouldered insulating block 22, saidblock being recessed to receive the terminal portions of the heatersheath and carrying on its outer face termina1 plates to which the leadwires l5 after passing through the block are secured, as best shown inFig. 6. The terminal portions of the heater sheath, as best shown inFig. 6, fit snugly in the recesses in the terminal block, and as shownin Fig. 7 the terminal block is rectangular in cross section to passthrough and to fit snugly within a rectangular opening in the mountingplate, said opening being shown by dotted lines in Figs. 2 and 3.

The gasket plate l'l, preferably brass, is circular, as shown in Fig. 2and in cross section is preferably of the shape shown in Fig. 5. Thus isprovided a circular central portion 25 having openings 26 and 21 toreceive the terminal portions of the heater sheath, and also an annularchannel 28 concentric with and offset from said central portion 25, saidchannel forming a retaining seat for an annular gasket l8. As will beunderstood, the diameter of the gasket plate is such as to enablecomplete closure by the plate of the opening in the wall I 9 forentrance of the heater, the gasket affording a seal between the plateand the wall. Also as will be understood, the joints between the heaterand the gasket plate are to be sealed as by silver soldering. Theterminal portions of the heater sheath are preferably projected throughthe gasket plate to extend somewhat beyond the oifset forming the gasketchannel and into recesses in the terminal block, said block beingreceivable by said gasket plate in the central pocket provided byoflsetting the gasket channel. As shown in Fig. 2, the outer flange ofthe gasket channel is notched for clearance of the bolts for attachingthe mounting plate to the receptacle, this provision being madeprimarily to adapt the mounting to existing receptacles but otherwisebeing unnecessary. As will be noted, this construction of the gasketplate materially increases its strength and rigidity as the support forthe heater.

The mounting plate Ell, preferably steel, is shown as being rectangularalthough it might be of other shapes, and is shown as having arectangular central opening which also might be of different contour tomatch the contour of the terminal block employed. Such plate, as will beunderstood, must be rugged and to obtain the required ruggedness withless material the plate is formed to offset from its central and cornerparts its intermediate mar 'inal parts, as best shown in Fig. 4, whichshows in edge elevation three corner parts 30 and two offsetintermediate marginal parts 3i. The degree of offset may be as desiredbut preferably it is as depicted in Fig. 4 which shows offsetting to adegree doubling the overall thickness of the plate.

The terminal block 22 is shown as having a rectangular portion 33fitting snugly within and extending through the central opening of themounting plate 28] and as also having an enlarged outer rectangularportion 34 to abut the mounting plate 28. Thus the mounting plate isconfined between the gasket plate and portion t l of the terminal blockwhen. said block is secured to the heater. The end of portion 33 of theterminal block, as best shown in Figs. 6 and 7, is provided with aprojecting and meandering rib bounded by lines 35 and 3t, which rib isaccommodated by the gasket plate within the space provided by offsettingthe gasket channel. The contour of the rib is such as to leave the blockwith inset corner ledges 31, all in the same plane, and said block hasat its four corners circular recesses 39 opening at such ledges, each toaccommodate with snug fit a heater sheath terminal portion. Where asingle heater of the form shown is employed. only two of the recesses 31are so utilized but it is preferred to form the block to make possiblethe use of two heaters, it being understood that in such event thegasket plate would be provided with additional openings. Two diagonallydisposed recesses 38 align with the gasket plate openings 26 and 2'3shown in Fig. 2, and as earlier explained the terminal portions of theheater sheath are projected through the gasket plate openings intorecesses 39 of the terminal block. The heater and the block are thusinterlocked against relative rotary play while the matching 4 contoursof the block and the receiving opening in the mounting plate interlocksaid block and plate against relative rotary play. The heater beingsupported by the gasket plate and said plate being of the ruggedconstruction shown it is unnecessary to have the heater sheath projectinto the insulating block farther than is required for interlockingpurposes, and hence the penetration need be no more than that shown inFig. 6.

However, the recesses 39 are preferably continued through the block topermit the heater lead wires to extend through and project beyond theouter end of the block, as shown in Fig. 6, for attachment to terminalplates seated on the block. The outer face of the block, as best shownin Figs. 3 and 6, has a transverse central rib W and parallel side ribsH of slightly less height which form with rib 4E3 two channels toreceive flat terminal plates 32, each extending substantially the fulllength of its channel to overlie two recesses 3% Midway between each twosuch recesses the ter minal block has a substantially rectangulardepression 43 and centrally thereof a further depression id of circularform. The terminal plates t? as shown each comprise rectangular endportions at connected by a narrower strip 46 to be straddled by aU-shaped plate ll. The legs of plate -ll' extend into recess t3 and saidplate which constitutes a wire clamping plate has passin therethroughwith a loose fit a binding screw @8 threading into the strip it of theterminal plate.

The end portions 45 of each terminal strip have therein openingsaligning with the block recesses 39, which said portions 45 overlie.Thus the heater lead wires may be projected through the block and theheater plates for securement to said plates by welding or in any otherpreferred manner. The heater and its associated mounting parts andterminal block are thus secured together in assembled relation.

As will be understood, where a single heater of the form shown isemployed it will be desired to employ two terminal plates of the formdescribed, connecting one of the heater leads to one plate and the otherheater lead to the other plate, preferably in the manner described. Itis to enable such connections that the heater is projected intodiagonally disposed recesses in the rectangular block. The attachment ofeach terminal plate at one end to its respective heater lead is adequateto retain the plates in place on the block and the two plates thussecured jointly afford adequate securement of all parts in assembledrelation.

Also as will be understood, where two heaters are employed it may bedesired to modify one or both terminal plates, but in any event each ofthe heater terminal leads will be secured to a terminal plate andcollectively the plates will aiiord equal or greater securement of theheater and its associated parts in assembled relation.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a sheathed electric immersion heater, a gasketclamping plate to close the entrance opening for said heater into areceptacle and to shield hereinafter specified elements, said heaterhaving its sheath projecting through said plate and having therewithfluid tight connection, an insulating terminal block into which theheater sheath projects with snug fit after passing through said plate, amounting plate through which said block extends, said mounting platebeing confined between the first mentioned plate and an abutting part ofsaid block,

and terminal plates located on the outer end of said block, to which theterminal leads of said heater are led through said block and to whichsaid terminal leads are secured for electrical connection therewith andfor securement of said block to said heater after assembly therewith ofsaid mounting plate.

2. In combination, a sheathed electric immersion heater, a plate toclose the entrance opening for said heater into a receptacle and toshield hereinafter specified elements, said heater having its sheathprojecting through said plate and having therewith fluid tightconnection, said shield plate being formed with a channel surroundingand offset laterally from its central portion, a gasket carried by saidplate in its said channel, an insulating block into which the heatersheath projects with snug fit after passing through said plate, amounting plate through which said block extends for entry into thecentral pocket rovided in said shield plate by ofiset of its gasketchannel, said mounting plate being confined between said shield plateand an abutting part of said block, and said block being secured to saidheater.

3. In combination, a sheathed electric immersion heater, a plate toclose the entrance opening for said heater into a receptacle and toshield hereinafter specified elements, said heater having its sheathprojecting through said plate and having fiuid tight connectiontherewith, said plate being formed with a channel surrounding and offsetlaterally from its central portion, a gasket carried by said plate inits said channel, an insulating block into which the heater sheathprojects with snug fit after passing through said shield plate, amounting plate through which said block extends for entry into thecentral pocket provided in said shield plate by ofiset of its gasketchannel, said mounting plate being confined between said shield plateand an abutting part of said block, and said block being secured to saidheater, said mounting plate having in the same plane a central portionand outwardly extending portions to receive attaching bolts and havingmarginal portions intermediate of said bolt receiving portions oflsetlaterally toward said shield plate.

4. A sheathed electric immersion heater having a gasket carrying plateto close and seal the entrance opening for said heater into areceptacle, said plate having a central portion through which saidheater projects and with which said heater has fiuid tight connection,and said plate having concentrically about its said central portion andoffset laterally therefrom an annular channel to receive and retain inplace its gasket.

5. In combination, a sheathed electric immersion heater, a plate toclose the entrance opening for said heater into a receptacle and toshield hereinafter specified elements, said shield plate having acentral portion through which said heater projects and with which saidheater has fluid tight connection, and said shield plate beingmarginally formed to provide a retaining seat for an annular gasketoffset laterally from and surrounding the central portion of said plate,and a mounting plate to bear against and clamp said shield plate to areceptacle, said mounting plate having in the same plane a centralportion and outwardly extending bolt receiving portions, and havingmarginal portions intermediate said bolt receiving portions offsettoward and clearing said shield plate.

6. In combination, a reflexed sheathed electric immersion heater, agasket plate to close the entrance opening for said heater into areceptacle and to shield hereinafter specified elements, said heaterhaving its sheathed ends projected through said plate and having fluidtight connection therewith, an insulating terminal block recessed toreceive the sheathed ends of said heater projecting from said plate, amounting plate through which said block extends, said mounting platebeing confined between said shield plate and an abutting part of saidblock, and separate terminal plates having definitely spaced seats onthe outer end of said block, said heater having its terminal leadsextended through said block and each through one of said terminalplates, and said terminal leads being secured to their respectiveterminal plates for electrical connection therewith and for securementof all aforesaid elements, including said terminal plates, in assembledrelation.

7. In combination, a refiexed sheathed electric immersion heater, agasket plate to close the entrance opening for said heater into areceptacle and to shield hereinafter specified elements, said heaterhaving its sheathed ends projected through said plate and having fluidtight connection therewith, an insulating terminal block recessed toreceive wit-h snug fit the sheathed ends of said heater projecting fromsaid plate, a mounting plate through which said block extends with a fitto prevent relative rotary play of said mounting plate, and saidmounting plate being confined between said gasket plate and an abuttingpart of said block, and separate terminal plates having definitelyspaced seats on the outer end of said block, said heater having itsterminal leads extended through said block and each through one of saidterminal plates, and said terminal leads being secured to theirrespective terminal plates for electrical connection therewith and forsecurement of all aforesaid elements, including said terminal plates, inassembled relation, said gasket plate being mar-- ginally offset towardsaid mounting plate to form a gasket seat, and said mounting platehaving in the same plane a central portion and outwardly extendingportions to receive securing bolts and having intermediate marginalportions ofiset towards but clearing said gasket plate.

ALLAN P. CHARBONNEAU.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,282,476 Simon Oct. 22, 19181,671,592 Kercher et a1 May 29, 1928 2,217,595 Morgan et al Oct. 8, 19402,274,445 Greer Feb. 24, 1942 2,412,737 Kercher Dec. 17, 1946

